1. Field of the Invention
This invention relates to an information storage medium, and more specifically to the reproduction of DVD disc having a video zone in which picture information and associated sound information are mainly recorded and an audio zone in which sound information is mainly recorded.
2. Description of the Prior Art
There is known a video DVD (i.e., a disc in conformity with the DVD-Video Standard) on which picture information such as movies are recorded. A video DVD is broadly used as an information storage medium for picture information such as movies because of its large storage capacity. Further, there has been developed an audio DVD (i.e., a disc in conformity with the Audio-DVD Standard) adapted to record, not picture information such as movies, but only audio information such as music. A single audio DVD can record audio information corresponding to plural CDs (Compact Disc) because of its large storage capacity. Also, in addition to picture information of a movie, audio information of a soundtrack CD for the movie can be recorded together on a single audio DVD.
In such circumstance, it is forecasted that a so-called compatible DVD player, having an ability to reproduce both audio DVD and video DVD, will be developed and used in the near future. However, simply recording video information and audio information on a single disc according to the DVD-Video Standard and the DVD-Audio Standard may restrict desired various manners of reproduction by the compatible DVD player. Specifically, the following drawbacks are presumable. First, since only the navigation information (i.e., a control information used to reproduce information) for video information is recorded in the video zone according to the DVD-Video Standard, only the audio information recorded in the video zone normally cannot be reproduced separately from the associated video information. In addition, the reproduction is limited to such manners that titles in the audio zone are reproduced and then titles in the video zone are reproduced, or in the reversed order. Namely, it is not possible to control the reproduction of all titles recorded in the video zone and audio zone of a single disc in an intermixed manner.